Resin packaging

ABSTRACT

This invention relates to packages, systems, and methods for protecting rosin-based resins, modified rosin resins, hydrocarbon resins and hydrocarbon modified resins suitable for use in the production of printing inks and other coatings from the effects of exposure to oxygen during transport and storage. In particular, this method involves the packaging of rosin-based resins, modified rosin resins, hydrocarbon resins and/or hydrocarbon modified resins at a temperature at least 5° F. below the glass transition temperature of the resin being packaged in sealed oxygen-transmission resistant enclosures from which a substantial portion of the oxygen has been evacuated.

FIELD OF INVENTION

This invention relates to packages, systems, and methods for protectingrosin-based resins, modified rosin resins, hydrocarbon resins andhydrocarbon modified resins suitable for use in the production ofprinting inks and other coatings from the effects of exposure to oxygenduring transport and storage. In particular, this method involves thepackaging of rosin-based resins, modified rosin resins, hydrocarbonresins and/or hydrocarbon modified resins at a temperature at least 5°F. below the glass transition temperature of the resin being packaged insealed oxygen-transmission resistant enclosures from which a substantialportion of the oxygen has been evacuated.

BACKGROUND OF THE INVENTION

It is well known that rosin exists in a number of forms. The term rosin,as used herein, includes tall oil rosin, wood rosin, gum rosin, crudematerials and mixtures containing any of the foregoing, and, in general,any materials containing abietic acid, including tall oil fractionscontaining various proportions of rosin and fatty acids. Hydrocarbonresins refer to products produced using materials such asdicyclopentadiene, cyclopentadiene, indene, vinyl toluene, and the like,which are derived from distillation of crude oil or natural gas.Rosin-based resins, modified rosin resins, hydrocarbon resins andhydrocarbon modified resins are chemically modified and polymerized toproduce products having from low to very high molecular weights based onthe required physical properties of the end user.

Rosin-based resins, modified rosin resins, hydrocarbon resins andhydrocarbon modified resins are commonly employed in a variety ofdifferent uses, including lithographic inks and other printing inkformulations, coating formulations, pigment resinating, dry grinding ofpigments and presscake flushing operations. However, a major problemexists in the industry concerning the transport and storage of theseresins. Rosin-based resins, modified rosin resins, hydrocarbon resinsand hydrocarbon modified resins are capable of reacting with molecularoxygen in a process known as autoxidation. These resins are particularlysusceptible to such reactions due to the existence of double bondsthroughout the resins. Autoxidation is essentially a free radicalprocess that can be initiated by heat. Free radicals are formed in theresin, which can react with molecular oxygen to form peroxy radicals.These peroxy radicals can further react with other organic material toform hydroperoxides. Hydroperoxides tend to be stable at temperatures ofless than 70° F., but can decompose at higher temperatures to generateadditional free radicals and continue to fuel the oxidation process.

The oxidation and peroxide formation are undesirable processes that canalter the physical properties of the rosin-based resins and modifiedrosin resins to such an extent that the resins are not longer suitablefor employment in the formulation of inks or coatings, or for variousother uses. Oxidation and peroxide formation can increase the viscosityof these resins, thereby making them less soluble—or even insoluble—inink oils. Furthermore, oxidized resins are more prone to absorbmoisture, which can be a major problem for coating producers. Forexample, should a coating producer attempt to dissolve oxidized resin ina hot ink oil system, the presence of excessive moisture can cause thevarnish to foam, thereby causing production and safety concerns.

It is common practice in the industry to flake rosin-based resins,modified rosin resins, hydrocarbon resins and hydrocarbon modifiedresins to facilitate their transportation and use in the production ofinks and coatings. The flaking of these resins provides optimalconditions for oxidation and peroxide formation, as the flaked resinstend to have relatively large surface areas exposed to oxygeninteraction.

Flaked rosin-based resins, modified rosin resins, hydrocarbon resins andhydrocarbon modified resins are commonly packaged in large containers(such as sacks containing from 50 to 2,500 pounds of resin and otherpackages) for transportation and storage. The problems of oxidation andperoxide formation in packaged rosin-based resins, modified rosinresins, hydrocarbon resins and hydrocarbon modified resins can beparticularly acute during the summer months and during extended periodsof transportation and/or storage.

Various methods have been utilized in attempts to deal with the problemof oxidation and peroxide formation in packaged rosin-based resins,modified rosin resins, hydrocarbon resins and hydrocarbon modifiedresins. One approach has been to keep the resins as cool as possible bymaintaining the packaged resins under temperature-controlled conditionsduring transportation and storage. However, the use of air-conditionedtransportation or warehousing can be comparatively expensive.

Another approach has been to place the rosin-based resins, modifiedrosin resins, hydrocarbon resins and hydrocarbon modified resinsdirectly into solution. However, pre-made resin solutions may restrictthe user's flexibility to formulate inks and other coatings.

Yet another approach to the problem of oxidation and peroxide formationhas been to add antioxidants to the packaged rosin-based resins,modified rosin resins, hydrocarbon resins and hydrocarbon modifiedresins to disrupt the free radical process. For example, hindered phenolantioxidants can be added to react with the peroxy radicals to forminactive species. Likewise, phosphites and thioethers can be added toreact with hydroperoxides to yield non-reactive products. Often thesetwo classes of antioxidants are employed together to achieve asynergistic effect. Such antioxidants are typically added to rosin-basedresins, modified rosin resins, hydrocarbon resins and hydrocarbonmodified resins at a rate of about 0.1% to about 2.0% on a weight basis.However, the use of such antioxidants is relatively expensive.

Therefore, an object of this invention is to solve these major problemsby disclosing a method of packaging rosin-based resins, modified rosinresins, hydrocarbon resins and/or hydrocarbon modified resins having atemperature at least 5° F. below the glass transition temperature of theresin being packaged in sealed oxygen-transmission resistant enclosuresfrom which a substantial portion of the oxygen has been evacuated.

Another object of this invention is to disclose packages for rosin-basedresins, modified rosin resins, hydrocarbon resins and/or hydrocarbonmodified resins used in the production of lithographic printing inks andother coatings.

A further object of this invention is to disclose a system for packagingrosin-based resins, modified rosin resins, hydrocarbon resins and/orhydrocarbon modified resins used in the production of inks and othercoatings.

SUMMARY OF THE INVENTION

The present invention achieves these objects and others by the packagingof rosin-based resins, modified rosin resins, hydrocarbon resins and/orhydrocarbon modified resins having a temperature at least 5° F. belowthe glass transition temperature of the resin being packaged in sealedoxygen-transmission resistant enclosures from which a substantialportion of the oxygen has been evacuated. It has been found that thepackaging of rosin-based resins, modified rosin resins, hydrocarbonresins and/or hydrocarbon modified resins in an oxygen-reducedatmosphere while they are at a temperature at least 5° F. below theirglass transition temperatures serves to prevent accelerated oxidation.Energy in the form of heat is generated during oxidation. By allowingadditional energy in the form of temperatures greater than about atleast 5° F. below the glass transition temperature of the resin, it ispossible to accelerate the oxidation process utilizing the trapped airwithin flaked resin (that is generated during the flaking process) andheat energy that releases the trapped air. Because the glass transitiontemperatures of rosin-based resins and modified rosin resins arecommonly in the range of about 120° F. to about 200° F., air trappedwithin the thin resin flakes can be released as the temperatureapproaches the glass transition temperature of the resin. Also, anymoisture that is present within the package can have the effect ofdistributing heat in a more even fashion, while also evenly distributingfree radicals formed during oxidation and continuing the progress tohydroperoxide formation. This process continues until the fuel sourcesin resin flakes have been consumed. In some cases, the initialtemperature and heat energy generated approaches temperatures whereesterfication (i.e., the chemical reaction commonly used to producerosin-based resins and hydrocarbon resins) begins. In these extremesituations, the resins can become molten and potentially exothermic(thereby generating water-formation and increasing the molecular weightof the resins in an uncontrolled fashion).

Packaging the rosin-based resins, modified rosin resins, hydrocarbonresins and/or hydrocarbon modified resins in sealed oxygen-transmissionresistant enclosures from which a substantial portion of the oxygen hasbeen evacuated serves to retard the oxidation process. Another furtheradvantage of vacuum sealing under pressure is that the compression ofthe brittle resin flakes can shatter the thin layers of resin that trapair with individual flakes, thereby freeing trapped air for evacuation.Additionally, vacuum sealing also serves to evacuate moisture that maybe present on the surface of flaked resin, thus helping to reducedistribution of heat energy.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The method of the present invention comprises packaging at least onemember selected from the group consisting of rosin-based resins,modified rosin resins, hydrocarbon resins, hydrocarbon modified resins,and combinations thereof at a temperature at least 5° F. below the glasstransition temperature of said resin in sealed oxygen-transmissionresistant enclosures from which a substantial portion of the oxygen hasbeen evacuated.

A further embodiment of the present invention comprises a method forpackaging resin, comprising the steps of:

-   -   1) providing resin selected from the group consisting of        rosin-based resins, modified rosin resins, hydrocarbon resins,        hydrocarbon modified resins and combinations thereof;    -   2) placing the resin in one or more oxygen-transmission        resistant, flexible packaging enclosures wherein each enclosure        has at least one sealable opening therein;    -   3) subjecting the packaging enclosures and the resin to a vacuum        force to remove a substantial portion of the oxygen from the        packaging enclosures;    -   4) sealing the flexible packaging enclosures while subjected to        the vacuum force such that upon sealing the packaging enclosure        contains an oxygen-reduced atmosphere, and wherein the resin has        a temperature at least 5° F. below its glass transition        temperature at the time of sealing.

In another embodiment, at least one member selected from the groupconsisting of rosin-based resins, modified rosin resins, hydrocarbonresins, hydrocarbon modified resins and combinations thereof having atemperature at least 5° F. below the glass transition temperature of theresin is placed within one or more oxygen-transmission resistant,flexible packages. Each package has at least one sealable openingtherein. The packages and the resins are then subjected to a vacuumforce. The vacuum force is maintained for a time sufficient to remove asubstantial portion of the oxygen from the package. While under theinfluence of the vacuum, the packages are sealed while maintaining theresin temperature and the vacuum force, rendering the package gasimpermeable while maintaining an oxygen-reduced atmosphere inside thepackage. Typically, the package is heat sealed shortly after initiatingthe vacuum, and usually not more than one-half hour after initiating thevacuum.

In another embodiment, at least one member selected from the groupconsisting of rosin-based resins, modified rosin resins, hydrocarbonresins, hydrocarbon modified resins and combinations thereof is placedwithin one or more containers (such as a sack or other package). Thecontainer(s) containing resin having a temperature at least 5° F. belowthe glass transition temperature of the resin is subsequently placedwithin one or more oxygen-transmission resistant, flexible packageswherein each package has at least one sealable opening therein. Thepackages, containers, and resin are then subjected to a vacuum force.The vacuum force is maintained for a time sufficient to remove asubstantial portion of the oxygen from the package. While under theinfluence of the vacuum, the packages are sealed while maintaining theresin temperature and the vacuum force, rendering the package gasimpermeable while maintaining an oxygen-reduced atmosphere inside thepackage. Typically, the package is heat sealed shortly after initiatingthe vacuum, and usually not more than one-half hour after initiating thevacuum.

In another embodiment, at least one member selected from the groupconsisting of rosin-based resins, modified rosin resins, hydrocarbonresins, hydrocarbon modified resins and combinations thereof that are tobe subjected to the method of the invention are first placed in anoxygen-transmission resistant flexible package that has at least onesealable opening therein. The package and the resin are then subjectedto a vacuum force while at least one sealable opening remains open. Thevacuum force is maintained for a time sufficient to remove a substantialportion of the oxygen from the package. Thereafter, the package issealed (preferably heat sealed) while the resin has a temperature atleast 5° F. below the glass transition temperature of the resin andwhile maintaining the vacuum force, rendering the package gasimpermeable while maintaining an oxygen-reduced atmosphere inside thepackage.

The package of the present invention comprises a sealed,oxygen-transmission resistant enclosure surrounding at least one memberselected from the group consisting of rosin-based resins, modified rosinresins, hydrocarbon resins, hydrocarbon modified resins and combinationsthereof, wherein said resin has a temperature at least 5° F. below theglass transition temperature of the resin at the time the enclosure issealed and wherein said package had a substantial portion of the oxygenevacuated from said package at the time the enclosure is sealed toproduce an oxygen-reduced atmosphere in said package. Where desired,more than one oxygen-transmission resistant enclosure may be employed.

The system of the present invention for packaging at least one memberselected from the group consisting of rosin-based resins, modified rosinresins, hydrocarbon resins, hydrocarbon modified resins and combinationsthereof comprises:

-   -   (a) means for forming a sealed, oxygen-transmission resistant        enclosure around said resin, and    -   (b) means for evacuating a substantial portion of the oxygen        from said enclosure prior to sealing of said enclosure to        produce an oxygen-reduced atmosphere within said enclosure at a        time when said resin has a temperature at least 5° F. below the        glass transition temperature of said resin.        Where desired, more than one oxygen-transmission resistant        enclosure may be employed.

Enclosures which are suitable for this method are oxygen-transmissionresistant. It is preferred that the oxygen-transmission resistantenclosures have an oxygen transmission rate (OTR) of less than about 200(preferably less than about 100 and more preferably less than about 50)cubic centimeters per square meter per day at atmospheric pressure and amoisture vapor transmission rate (MVTR) of less than about 90(preferably less than about 50 and more preferably less than about 15)grams per square meter per day at atmospheric pressure. Suitable typesof enclosures include, but are not limited to, the following: bags,sheets, liners, metal containers, composite containers, and the like.Packaging materials that are suitable for use in the enclosure withinwhich the rosin-based resins, modified rosin resins, hydrocarbon resins,and/or hydrocarbon modified resins are sealed can be selected from amongthe many types of high barrier, oxygen transmission resistant, packagingmaterials. Such packaging materials include, but are not limited to, thefollowing: nylons, polyethylenes, foils, plastics, EVOH, compositematerials, and combinations thereof. The thickness of the packagingmaterial is preferably in the range of about 4 millimeters to about 50millimeters.

It is preferred that the oxygen-transmission resistant enclosure be aheat sealable bag. The type of bag or other enclosure used to packagethe resin is chosen based on the characteristics of the resin productbeing packaged and the desired use of the package. It is well within theability of one skilled in the art to determine the type of enclosure tobe employed for desired package uses.

It is further preferred that the enclosure employed in the sealingprocess be a 4.5 millimeter nylon and polyethylene fused layered liner.The nylon characteristics include a very low OTR of 30-50 cubiccentimeters per square meter per day at atmospheric pressure, an MVTR of5-15 grams per square meter per day, and the formability to allow theenclosure to conform to the shape of the original bulk sack or othercontainer. The polyethylene characteristics include a very low MVTR andlow OTR, good formability properties, and excellent sealability. Thepolyethylene layer is a lower cost barrier material that providesthickness for durability. Durability of packaging is important as resinpackages are commonly transported to customers by truck and handledmultiple times until opened and used by customers. During handling, itis important to provide a durable package to withstand handling andtransportation while maintaining an oxygen-reduced atmosphere within thepackage.

It is further preferred that the rosin-based resins, modified rosinresins, hydrocarbon resins, and/or hydrocarbon modified resins be firstpackaged in a sack or other container prior to enclosure in theoxygen-transmission resistant enclosure. The sack is then sealed in theenclosure from which a substantial portion of the oxygen has beenevacuated. At the time the enclosure is sealed to produce anoxygen-reduced atmosphere within the enclosure, the resin(s) containedin the enclosure should have a temperature at least 5° F. below theglass transition temperature of the resin(s).

The method or means by which the oxygen is evacuated from the enclosureto produce an oxygen-reduced atmosphere is not critical, in that theoxygen may be evacuated in any suitable manner that does not adverselyeffect the OTR and MTVR characteristics of the enclosure or the chemicalcharacteristics of the rosin-based resins, modified rosin resins,hydrocarbon resins, and/or hydrocarbon modified resins. Suitable methodsinclude, but are not limited to, the following: purging with at leastone inert gas (such as nitrogen, argon, helium, neon, etc.), vacuumsealing, and the like. It is preferred to maintain a vacuum force toremove a substantial portion of the oxygen while sealing the enclosure,thereby rendering it impermeable to gases.

As used herein, the removal of a “substantial portion of the oxygen” isthe removal of an amount of oxygen sufficient to impede oxidation of therosin-based resins, modified rosin resins, hydrocarbon resins, and/orhydrocarbon modified resins. It is preferred to remove substantially allof the oxygen from the enclosure, and it is further preferred to removeall of the oxygen from the enclosure.

A preferred method of oxygen evacuation is a combination of inert gaspurging and vacuum sealing. It is further preferred to employ at leastone sack (or other container) to contain the rosin-based resins,modified rosin resins, hydrocarbon resins, and/or hydrocarbon modifiedresins. The sack(s) containing the rosin-based resins, modified rosinresins, hydrocarbon resins, and/or hydrocarbon modified resins is placedwithin an enclosure (preferably a heat sealable bag), then subjected toa first purge with inert gas (preferably nitrogen) to displace anddilute the oxygen content. The gas is then vacuumed out of the enclosurebag to 6.93 pounds per square inch gage. The enclosure bag is purged asecond time with inert gas (preferably nitrogen) to further dilute anyremaining oxygen and a second vacuum is pulled to 6.93 pounds per squareinch gage vacuum. The enclosure is then sealed to maintain theoxygen-reduced atmosphere within the enclosure. At the time theenclosure is sealed, the resins contained in the enclosure have atemperature at least 5° F. below their glass transition temperatures.

Rosin-based resins, modified rosin resins, hydrocarbon resins, and/orhydrocarbon modified resins which are suitable for use in the productionof lithographic inks, printing inks, coatings, pigment resinating, drygrinding of pigment and/or presscake flushing operations may be used inthe present invention. Suitable modified rosin resins include, but arenot limited to, the following: maleic-modified rosin resins,phenolic-modified rosin resins, fumaric-modified rosin resins and thelike. It is preferred that the rosin-based resins, modified rosinresins, hydrocarbon resins, and/or hydrocarbon modified resins be flakedprior to packaging within the oxygen oxygen-transmission resistantenclosure.

It is critical that the temperature of the rosin-based resins, modifiedrosin resins, hydrocarbon resins, and/or hydrocarbon modified resins beat least 5° F. below the glass transition temperature of the resin beingpackaged at the time the enclosure is sealed. If more than one resin isbeing packaged in the enclosure, then the temperature of the resinsbeing packaged at the time the enclosure is sealed should be at least 5°F. below the lowest of the glass transition temperatures of the packagedresins. It is preferred that the temperature of the resin be less thanabout 100° F. at the time the enclosure is sealed, more preferably lessthan about 80° F., and more preferably less than about 70° F.

It has been found that the packaging of the rosin-based resins, modifiedrosin resins, hydrocarbon resins, and/or hydrocarbon modified resins inan oxygen-reduced atmosphere while they are at a temperature at least 5°F. below their respective glass transition temperatures serves toprevent accelerated oxidation. Energy in the form of heat is generatedduring oxidation. By allowing additional energy in the form oftemperatures near or at the glass transition temperature of the resin,it is possible to accelerate the oxidation process utilizing the trappedair within flaked resin (that is generated during the flaking process)and heat energy that releases the trapped air. Because the glasstransition temperatures of rosin-based resins and modified rosin resinsare commonly in the range of about 120° F. to about 200° F., air trappedwithin the thin resin flakes can be released as the temperatureapproaches the glass transition temperature of the resin. Also, anymoisture that is present within the package can have the effect ofdistributing heat in a more even fashion, while also evenly distributingfree radicals formed during oxidation and continuing the progress tohydroperoxide formation. This process continues until the fuel sourcesin the resin flakes have been consumed. As a function of this process,it has been determined that vacuum sealing is most effective attemperatures lower than about 70° F. and at relative humidities lowerthan about 60%. It is preferred that the relative humidity be as low aspossible. One skilled in the art would recognize that barrier materialscan also change with these process conditions and become a contributingfactor in the OTR and MVTR rates. Likewise, OTR and MVTR rates increasewith elevated temperatures and higher humidities.

The following examples are provided to further illustrate the presentinvention and are not to be construed as limiting the invention in anymanner.

EXAMPLE 1

A series of tests were conducted evaluating the effect of packaging andstorage on the oxidation, viscosity, and dilution characteristics ofhard resins. For comparison purposes, samples of HC-910 (a flakedhydrocarbon modified rosin resin having a glass transition temperatureof 82.2° C. commercially available from MeadWestvaco Corporation) wereevaluated under two conditions. As a control, 500 grams of resin wasplaced in a tray and left exposed to atmosphere (hereinafter “tray”sample). In the second evaluation, 100 grams of resin were placed ineach of sixteen separate polyethylene plastic bags, vacuum was appliedto remove a substantial proportion of the air out of the bag, and thebags were then heat sealed to form sealed enclosures havingoxygen-reduced atmospheres (hereinafter “vacuum bag” samples). Theresins were packaged at a temperature of about 73° F. and a relativehumidity of about 30%. The respective resin samples were subsequentlystored at 110° F. to simulate typical summertime warehouse conditions.

The evaluations were based on a run of two samples per week over a52-day period. The tests run on each sample throughout the testingperiod were 1:2 ARLO solution line-to-line seconds viscosity, % M-47dilution, and a cloud point determination using the Chemtronic I with10% resin and 90% PKWF®6/9 Test oil (a test oil commercially availablefrom Haltermann GmbH). The 1:2 ARLO test is a standard industry relatedtest (ASTMD 1725-62, American Society for Testing and Materials), where1 part of resin is added to 2 parts of ARLO (alkaline refined linseedoil) heated to 215° C. The solution is then added to a viscosity tube(bubble tube), controlled to 25° C., and the viscosity is measured as anair bubble travels the length of the tube (with the viscosity recordedin seconds). The prepared solution is also titrated with MagieSol® 47 (adistilled mineral oil commercially available from Magie Bros.) andrecorded in percentage of oil added to prepared ARLO solution, which isalso a standard industry related test (ASTMD 5062-96). The cloud pointtest employed a Chemotronic Automatic Cloud Point Tester, wherein asolution of resin and ink oil is heated at a controlled rate to 230° C.with stirring, then cooled at a controlled rate, to record the point ofresin kick out (cloud point) using a photo electric sensor. The resinsinitially had a 1:2 ARLO solution line-to-line seconds viscosity of 130seconds, a % M-47 dilution of 141%, and a cloud point determination of129° C. The test results are shown in Table I below. TABLE I RESINPACKAGING Day # Sample V1:2 (sec.)¹ % M-47 Dil.² Cld Point (° C.)³ 3Tray 138 125 138 Vacuum Bag 134 136 126 10 Tray 176 121 155 Vacuum Bag143 127 130 14 Tray 190 105 143 Vacuum Bag 129 152 129 17 Tray 209  99162 Vacuum Bag 136 137 129 21 Tray 357  86 141 Vacuum Bag 132 133 124 25Tray 308  77 208 Vacuum Bag 168 128 131 29 Tray Insoluble Insoluble 147Vacuum Bag 155 117 129 35 Tray Insoluble Insoluble 190 Vacuum Bag 155137 135 38 Tray Insoluble Insoluble 191 Vacuum Bag 141 126 131 42 TrayInsoluble Insoluble Insoluble Vacuum Bag 136 126 135 49 Tray InsolubleInsoluble 210 Vacuum Bag 174 118 129 52 Tray Insoluble InsolubleInsoluble Vacuum Bag 176 114 132¹V1:2 (sec) = 1:2 ARLO solution line-to-line viscosities.²% M-47 Dil. = % M-47 dilution.³Cld Point = cloud point determination in ° C. using a Chemtronic I with10% resin and 90% PKWF 6/9 Test oil.

The viscosity results in Table I show the atmospheric sample going outof specification (i.e., 135-195 line to line seconds) at day 21 oftesting and insoluble at day 35. In contrast, the vacuum bag samplesstayed in specification over the entire period with only a slightincreasing trend in viscosity.

Dilution results show a larger negative sloping trend on the atmosphericsample. The atmospheric sample is out of specification (i.e., % M-47dilution of 130-180%) low in dilution at day 7 of testing, and insolubleat day 29. Dilutions on the vacuum bag samples were able to stay inspecification until day 21. At no time did the vacuum bag samples fallbelow 110% M-47 dilution level (which is extremely favorable).

Cloud point measurements for vacuum bag samples stayed constantthroughout the testing period. In contrast, the atmospheric sample'scloud point rose at a steady rate with each test until the 38^(th) daywhen no cloud point could be obtained due to insolubility. The cloudpoint measurements of the atmospheric samples tended to vary somewhatdue to the relative exposures to oxygen of the surface areas of theindividual flakes.

EXAMPLE 2

A rosin resin can be packaged by the following method. Two thousandpounds of flaked hard rosin resin can be placed into a super sack. Thesuper sack containing the resin can be placed within a nylon andpolyethylene fused layered liner enclosure bag, which can then besubjected to a first purge with nitrogen to displace and dilute theoxygen content therein. The nitrogen gas can then vacuumed out of theenclosure bag to about 6.9 pounds per square inch gage. The enclosurebag can then purged a second time with nitrogen gas to further diluteany remaining oxygen and a second vacuum can be pulled to about 6.9pounds per square inch gage to remove the gas and produce anoxygen-reduced atmosphere. The enclosure bag can then be sealed tomaintain the oxygen-reduced atmosphere within the enclosure bag. At thetime the enclosure bag is sealed, the resins contained in the enclosurebag have a temperature at least 5° F. below their glass transitiontemperatures.

Many modifications and variations of the present invention will beapparent to one of ordinary skill in the art in light of the aboveteachings. It is therefore understood that the scope of the invention isnot to be limited by the foregoing description, but rather is to bedefined by the claims appended hereto.

1. A method for packaging resin, comprising the steps of: a) providingresin selected from the group consisting of rosin-based resins, modifiedrosin resins, hydrocarbon resins, hydrocarbon modified resins, andcombinations thereof; b) placing said resin in one or moreoxygen-transmission resistant, flexible packaging enclosures whereineach enclosure has at least one sealable opening therein; c) subjectingthe packaging enclosures and said resin to a vacuum force to remove asubstantial portion of the oxygen from the packaging enclosures; and d)sealing the flexible packaging enclosures while subjected to the vacuumforce such that upon sealing the packaging enclosure contains anoxygen-reduced atmosphere, and wherein said resin has a temperature atleast 5° F. below its glass transition temperature at the time ofsealing.
 2. The method of claim 1 wherein the resin is flaked.
 3. Themethod of claim 1 wherein the resin has a temperature of less than about100° F.
 4. The method of claim 1 wherein the resin has a temperature ofless than about 70° F.
 5. The method of claim 1 wherein the packingenclosure has an oxygen transmission rate of less than about 200 cubiccentimeters per square meter per day at atmospheric pressure.
 6. Themethod of claim 1 wherein the packing enclosure has a moisture vaportransmission rate of less than about 90 grams per square meter per dayat atmospheric pressure.
 7. A package for resins comprising a sealed,oxygen-transmission resistant enclosure surrounding at least one resinselected from the group consisting of rosin-based resins, modified rosinresins, hydrocarbon resins, hydrocarbon modified resins, andcombinations thereof, wherein said resin has a temperature at least 5°F. below its glass transition temperature at the time the enclosure issealed and wherein said package had a substantial portion of the oxygenevacuated from said package at the time the enclosure is sealed toproduce an oxygen-reduced atmosphere in the package.
 8. The package ofclaim 7 wherein the resin is flaked.
 9. The package of claim 7 whereinthe resin has a temperature of less than about I 00° F. at the time theenclosure is sealed.
 10. The package of claim 7 wherein the resin has atemperature of less than about 70° F. at the time the enclosure issealed.
 11. The package of claim 7 wherein the enclosure has an oxygentransmission rate of less than about 200 cubic centimeters per squaremeter per day at atmospheric pressure.
 12. The package of claim 7wherein the enclosure has a moisture vapor transmission rate of lessthan about 90 grams per square meter per day at atmospheric pressure.13. A system for packaging at least one resin selected from the groupconsisting of rosin-based resins, modified rosin resins, hydrocarbonresins and hydrocarbon modified resins and combinations thereofcomprising: a) means for forming a sealed, oxygen-transmission resistantenclosure around said resin, and b) means for evacuating a substantialportion of the oxygen from said enclosure prior to sealing of saidenclosure to produce an oxygen-reduced atmosphere within said enclosureat a time when the enclosed resin has a temperature at least 5° F. belowits glass transition temperature.
 14. The system of claim 13 wherein theresin is flaked.
 15. The system of claim 13 wherein the resin has atemperature of less than about 1 00° F. at the time the enclosure issealed.
 16. The system of claim 13 wherein the resin has a temperatureof less than about 70° F. at the time the enclosure is sealed.
 17. Thesystem of claim 13 wherein the enclosure has an oxygen transmission rateof less than about 200 cubic centimeters per square meter per day atatmospheric pressure.
 18. The system of claim 13 wherein the enclosurehas a moisture vapor transmission rate of less than about 90 grams persquare meter per day at atmospheric pressure.